This disclosure relates to the measurement of liquid levels in recreational vehicle wastewater holding tanks.
Many recreational vehicles, such as campers, trailers, fifth wheelers, and motor homes, have one or more tanks for storing the effluent or wastewater originating in the toilet, sink, or shower. These tanks are typically called black water or gray water tanks. The effluent stored in black water and gray water tanks can easily clog or render inoperable a liquid level measurement apparatus or sensors in direct contact with the wastewater. Examples of typical direct wastewater measurement devices are ones that use conductance, capacitance, floats, or other direct means for measuring the liquid in a tank. Despite the numerous cleaning methods and chemicals that have been developed, many of the existing wastewater level measuring methods and systems can fail within several weeks, resulting in the owner of a recreational vehicle draining the wastewater tank or tanks too frequently or running the risk of a tank overflow.
A typical modern recreational vehicle has a plurality of wastewater holding tanks. There are normally separate tanks for black water (human waste from the toilet) and gray water (waste water from the kitchen sink). There may be a second gray water tank for effluent from a shower.
Indirect liquid level measurement systems exist. One example is U.S. Pat. No. 7,389,688 by John Vander Horst. These devices work, but it was desired to make a simpler purely mechanical device that requires no transducers and is capable of measuring the liquid level in multiple tanks using a single gage.